Add/Remove is free and works very effectively when sent via email. Just create a new email and use the attachment feature to attach a file to the email. Select the .EXE for for Add/Remove and choose to attach it to the email. Once Add/Remove is attached to your email you can send it to your friends.

When they receive the email they will have to click on the attachment and save it or run it directly from the email. There is no way to have Add/Remove automatically run when the email is opened.